1. Field of the Invention
This invention relates to a multi-stage hyper-velocity kinetic energy (KE) missile. The missile may be configured for use with different platforms and different guidance systems but is particular well suited for use with a class of tactical missiles including an existing base of Tube-Launched, Optically-Tracked, Wire-Guided (TOW) launch platforms using command line of sight (CLOS) guidance to provide hyper-velocity KE-rod penetrator capability.
2. Description of the Related Art
The TOW missile was first produced in 1970 and is the most widely used anti-tank guided missile in the world. As shown in FIGS. 1a-1b and 2a-2b, a standard TOW missile 10 is a single-stage missile that delivers a chemical explosive to pierce the armor and destroy the tank. The missile is stored in a tow launch container (TLC) 12 that accommodates a missile of no more than 5 feet in length, 6 inches in diameter and at most 70 lbs. The TLC is mounted on a TOW platform such as a Bradly 14, Stryker 16, Humvee, Jeep, Helicopter etc.
The TOW weapons system uses CLOS to acquire, aim and maneuver the TOW missile to impact a target. This means that the guidance system is directly linked to the platform, and requires that the target be kept in the shooter's line of sight until the missile impacts. A typical TOW system uses Semi-Automatic CLOS in which target tracking is performed manually by an operator while missile tracking and control is automatic. The CLOS system 18 includes an optical sensor on the launch platform that images both the target and a beacon on the back of the TOW missile. The CLOS system uses only the angular coordinates between the missile and the target to ensure the collision. The missile will have to be in the line of sight between the launcher and the target (LOS), correcting any deviation of the missile in relation to this line. Early versions of TOW transmitted the guidance commands from the platform to the TOW missile over a wire, hence the name “Wire-Guided”. More recent versions have replaced the wire with an RF link. The TOW missile includes a CLOS flight control system 20 to maneuver the missile in response to the received guidance commands to impact the target. For a human operator to effectively target and maneuver the TOW missile to impact the target, the flight velocity of the TOW is less than Mach 1.5 and typically sub-sonic (i.e. less than Mach 1). There is a direct trade off of velocity to close the range to target versus the ability of an operator to control the missile.
The standard TOW missiles have been widely used against armour in the past and still have a role but are less effective against modern composite armour. Weapons systems that use KE-rod penetrators are being developed that are capable of piercing modern composite armour. The principle of the kinetic energy penetrator is that it uses its kinetic energy, which is a function of mass and velocity, to force its way through armour. The modern KE weapon maximizes KE and minimizes the area over which it is delivered, e.g. a metal rod several feet in length and approximately one inch in diameter travelling at hyper-velocities (>Mach 5).
The industry has been endeavoring for several years to develop a hyper-velocity KE missile that is backward compatible with both the operational and physical constraints of the existing deployed base of TLC and TOW platforms. The cost of discarding or modifying the TOW infrastructure is simply prohibitive. Such a missile would have to satisfy the size and weight constraints of the TLC, operational constraints of storing, loading and firing the missile and the guidance constraints of CLOS guidance. The missile would also have to satisfy the performance constraints of a KE-rod penetrator to deliver the penetrator on target at hyper-velocity.
One example of a KE-rod penetrator is the LM CKEM/LOSAT class of missiles that boost the missile to hyper-velocity over the entire effective range to target. These missiles are heavy, 100 lbs or more, and require a different guidance system. A human operator cannot target and maneuver a missile at hyper-velocity. Furthermore, the propellants required for hyper-velocity are very ‘smokey’ which occludes the operator's vision of the target.
Another example of a KE-rod penetrator is the HATEM class of missiles that boost the missile to hyper-velocity, separate the free-flying KE-rod (no separate boost capability) and guide the rod to impact the target. These missiles are heavy, 100 lbs or more and CLOS is not effective for the same reasons of hyper-velocity and the smoke cloud and additionally because the small diameter rod does not support the required beacons.
With the repeated failure of different KE architectures to both satisfy the TOW physical, operational and guidance constraints while providing effective KE performance the industry is largely resigned that KE technology cannot be effectively retrofitted to the TOW platform. The consensus is that the amount of propellant required for hyper-velocity flight will violate the size and weight constraints and that hyper-velocity flight is incompatible with CLOS guidance.